Service Diagnosis - Scotsman CU1526 Service Manual

Service Diagnosis

Problem
Shut down on maximum
freeze time
Likely Cause
Pump hose disconnected
Compressor not operating
Low refrigerant charge
Hot gas valve leaks through during
freeze
Thermostatic expansion valve bulb
loose
Thermostatic expansion valve
producing very low or very high
superheat
Compressor inefficient
May 2008
Page 29
CU1526, CU2026, CU3030
Service Manual
Probable Solution
Check hose
Check compressor contactor,
check controller using test mode
Check compressor start
components, check PTCR
resistance and temperature
Check compressor voltage
Check compressor windings
Add some refrigerant and restart
unit. If cycle time improves, look for
leak.
Check hot gas valve for hot outlet
during freeze
Check bulb
Check evaporator superheat,
change TXV if incorrect
Check compressor amp draw, if
low and all else is correct, change
compressor